Typical system architecture and procedures within the oil and gas industry may require operations to be performed within fluid conduits such as pipelines and wellbores, for example open hole wellbores or wellbore tubulars. For example, seals are frequently used to seal a fluid conduit, or a region such as an annular region defined within the fluid conduit, for zonal isolation, to establish a desired pressure for tool setting or the like. Such seals may be provided by packers, such as mechanical packers, inflatable packers, swellable packers or the like. Bridge plug and straddle tools may also include such seals. Furthermore, it is known to use anchors such as mechanical anchors within a fluid conduit to secure a component within the fluid conduit.
In most cases, equipment for use in performing operations in fluid conduits, such as packers, bridge plugs, straddles, anchors and the like, must be run into the fluid conduit while in a configuration which defines a minimal outer dimension to prevent snagging within the fluid conduit and permit passage through any fluid conduit restrictions. Such equipment must be capable of being reconfigured to define a larger dimension once at a desired position within the fluid conduit, for example to engage a fluid conduit wall for sealing or anchoring purposes, to actuate another tool or the like. However, high expansion ratios are difficult to achieve, and it is well known in the art that excessive expansion ratios are typically only achievable at the expense of performance. For example, a highly expanded seal may perform poorly against high pressures and may be susceptible to axial leakage and extrusion. Furthermore, a highly expanded anchor may be incapable of providing adequate gripping force.
Depending on environmental conditions, conventional seals may also be susceptible to failure even at low or zero expansion ratios. For example, conventional elastomer seals may be susceptible to extrusion at high pressures even at low or zero expansion ratios. Furthermore, when used in high pressure environments, conventional elastomer seals may become saturated with fluid and may be susceptible to failure by explosive decompression. Other known failure modes of conventional elastomer seals include temperature and chemical degradation. To mitigate at least some of these problems, it is known to reinforce conventional elastomer seals, for example, using metal such as wire mesh. However, even reinforced elastomer seals may be inadequate for some applications.
US 2003/0066640 discloses a known apparatus for injecting the fluid into a borehole. The apparatus includes a body adapted for passage through a borehole, at least four radially extendable and retractable zone interface elements spaced longitudinally along the body which when extended define at least three zones along the body, a zone interface element actuator for selectively extending and retracting the zone interface elements, and a fluid delivery system for delivering the fluid to each zone.
U.S. Pat. No. 6,182,755 discloses an annular seal made of a collapsible bellows. The bellows is expanded for insertion to reduce its outer dimension and sets by compaction as a result of relative movement. The bellows can be straight or tapered.
US 2009/0205817 discloses a packer assembly comprising a tubular member and a packer system circumferentially overlies the tubular member. The packer system includes end portions and the central portion disposed between the end portions. The central portion and the end portions are formed of material that swells when contacted with a swelling fluid. The central and end portions are constructed to swell upon contact with the swelling fluid so that the central portion swells to a diameter defined by a wall of the wellbore more rapidly than the end portions. In such a configuration, the central portion of the packer system can be fully swollen prior to the full swelling of the end portions.
US 2009/0242189 discloses our swell packer including a base tubular, a seal member encircling the base tubular, the seal member swelling radially to a seal equilibrium swell upon contact with particular fluid, and a disc positioned about the base tubular substantially abutting an end of the seal member but not physically connected to the seal member in a manner that limits the equilibrium swell of the seal member, the disc swelling radially to a first equilibrium swell upon contact with a particular fluid.